CHAPTER 5 ELBOW/FOREARM Copyright © 2019 Wolters Kluwer • All Rights Reserved

Anatomic Structures: Elbow/Forearm Region Whereas the shoulder aids in positioning an individual’s hand to perform functional movements, the elbow refines these positions. Bones of the elbow/forearm region Elbow is a hinge joint, made up of the following bones: Humerus Primary articulation—ulna Medial and lateral epicondyles—2 most prominent landmarks Other important features of the distal humerus are: Lateral supracondylar ridge Trochlea Trochlear groove Capitulum Coronoid fossa Radial fossa Olecranon fossa Copyright © 2019 Wolters Kluwer • All Rights Reserved

Anatomic Structures: Elbow/Forearm Region—(cont.) Radius Articulates with the humerus proximally, forming the humeroradial joint Articulates with the proximal and distal ulna forming the proximal radioulnar and distal radioulnar joints In forearm supination—radius/ulnar are parallel In forearm pronation—radial head spins on the ulna, crossing over (proximally) Provides attachment sites for musculature Bony features include: Radial head Fovea of radius Radial neck Radial tuberosity (attachment site for the biceps brachii) Shaft Radial styloid process Copyright © 2019 Wolters Kluwer • All Rights Reserved

Anatomic Structures: Elbow/Forearm Region—(cont.) Ulna Primary articulation between the humerus and ulna—humeroulnar joint Snug fit with humerus is through joint capsule & ligamentous structures Several important articulating surfaces and features for muscle attachments for optimal function include: Olecranon process Coronoid process Trochlear notch Trochlear ridge Ulnar tuberosity Radial notch Ulnar styloid Copyright © 2019 Wolters Kluwer • All Rights Reserved

Anatomic Structures: Elbow/Forearm Region—(cont.) Joints & their characteristics: Humeroulnar joint: Articulation of the trochlea—trochlea notch of the ulna Carrying angle of 15 degrees—functionally allowing for objects to be carried away from the body Capsule that surrounds joint allows for mobility Ligamentous structures stabilize joint Humeroradial joint: Articulation of the capitulum of the humerus—head of the radius Primary function—allows supportive motion to the elbow Permits flexion and extension motions—provides the joint stability due to its bony structure and strong ligamentous structures Proximal radioulnar joint: Articulation of the proximal ends of the two forearm bones—the radius/ulna Assists with the radius pivoting around the ulna during supination/pronation Note: Distal Radioulnar Joint allows for full forearm rotation (see explanation in detail in Chapter 6). Copyright © 2019 Wolters Kluwer • All Rights Reserved

Anatomic Structures: Elbow/Forearm Region—(cont.) Ligamentous structures 3 supporting ligamentous structures—stabilize the elbow Radial collateral Ulnar collateral Annular ligaments Radial collateral ligament Located on the lateral aspect of the elbow—connects the lateral epicondyle to the annular ligament of the radius Provides lateral strength to the elbow joint Ulnar collateral ligament Located & provide strength/stability on the medial aspect of the elbow—has three bands to support the elbow Anterior (cord-like) Posterior (fan-like) Oblique bands Copyright © 2019 Wolters Kluwer • All Rights Reserved

Anatomic Structures: Elbow/Forearm Region—(cont.) Ligamentous structures—(cont.) Annular ligament Encases the radial head & attaches to the ulna Function is to: Stabilize the radial head in the ulna’s radial notch Secure the radius to the ulna at the proximal joint Allows the radius to rotate during forearm supination/pronation motions Bursae Sacs containing synovial fluid that help minimize friction in areas subject to stress. Absorb excessive forces that are applied to the elbow joint, from high impact daily activities or trauma. Seven bursae surround the elbow joint—largest is the olecranon bursa. Copyright © 2019 Wolters Kluwer • All Rights Reserved

Arthrokinematics & Osteokinematics: Elbow/Forearm Region Arthrokinematics (accessory motions) Simultaneous, small movements occur within the elbow joint specifically: Humeroulnar joint—Ulnar trochlear notch (concave) rolling and gliding posteriorly on the humeral trochlea (convex) as the elbow moves into full extension. An anterior roll and glide also occurs in the same direction during elbow flexion. Proximal radioulnar joint—Anteromedial gliding of the radius on the ulna during forearm rotation, includes spinning of the radial head (convex) into the radial notch of the ulna (concave). An anteromedial gliding of the radius on the ulna during supination and a posterolateral gliding of the radius on the ulna during forearm pronation. Distal radioulnar joint—Movement occurs during forearm rotation, whereby the radius glides and rolls around the ulnar head in the same direction. Osteokinematics Extension/Flexion Rotation Copyright © 2019 Wolters Kluwer • All Rights Reserved

Functional Movement Patterns: Elbow/Forearm Elbow has: Unique design and tight geometric fit—promotes great stability, and more importantly, functional mobility. Anatomic design and forearm musculature allow for immediate elbow flexion, with the forearm in different positions. Limitations of forearm ROM (whether limited at proximal radioulnar joint or distal radioulnar joint) affect one’s ability to function efficiently within their environment. Copyright © 2019 Wolters Kluwer • All Rights Reserved

Palpation: Elbow/Forearm Region Palpation of surface landmarks with your partner: Lateral epicondyle Medial epicondyle Olecranon Ulnar styloid Distal radioulnar joint: Lister’s tubercle Radial head Copyright © 2019 Wolters Kluwer • All Rights Reserved

ROM Measurements: Elbow/Forearm Region Goniometry: Elbow Extension Flexion Forearm rotation Supination Pronation Let’s Practice Copyright © 2019 Wolters Kluwer • All Rights Reserved

Goniometric Measurements (ROM): Elbow/Forearm—(cont.) Discussion Questions: What are the normative values for forearm rotation? What is a functional task that the practitioner may observe for forearm supination? What is a best practice that you can do to minimize shoulder compensation when measuring ROM of forearm pronation? (Refer to page 112.) Clinical Note: When assessing forearm supination, observe the client’s trunk for compensatory motions. Copyright © 2019 Wolters Kluwer • All Rights Reserved

Functional Muscle Movers: Elbow/Forearm Region Extension: Triceps brachii Anconeus Flexion: Biceps brachii Brachialis Brachioradialis Supination: Supinator Pronation: Pronator teres Pronator quadratus Copyright © 2019 Wolters Kluwer • All Rights Reserved

Manual Muscle Testing (MMT): Elbow/Forearm Region Extension Flexion Forearm rotation Supination Pronation Let’s Practice Copyright © 2019 Wolters Kluwer • All Rights Reserved

Manual Muscle Testing (MMT): Elbow/Forearm Region— (cont.) Isolated testing elbow: Biceps brachii Brachialis Brachioradialis Isolated testing forearm: Supinator muscle Pronator teres Pronator quadratus Let’s Practice Copyright © 2019 Wolters Kluwer • All Rights Reserved

Manual Muscle Testing (MMT): Elbow/Forearm Region—(cont.) Discussion Questions: If you are testing a client for elbow extension in the gravity-minimized plane, what position would you place their extremity in? (See page 114.) Based on the manual’s grading scale, what Grade would give the client for full elbow extension in the gravity-minimized plane? What are the functional muscle movers for elbow extension? (See page 113.) Clinical Note: For an alternative start position for elbow extension – gravity resistance test, placing the client in the supine position; with the upper extremity in approximately 135° of shoulder elevation, the elbow fully flexed, and the fingers touching the spine of the scapula. Copyright © 2019 Wolters Kluwer • All Rights Reserved

Summary: Elbow/Forearm Region The elbow allows adjustments in height and length of the upper extremity, permitting one to position the hand correctly, thus assisting in maximizing functional hand use for effective manipulation of one’s environment. Copyright © 2019 Wolters Kluwer • All Rights Reserved